1. Field of Invention
This invention relates to a composition comprising at least one halogenated organic compound and a stabilizer. More particularly, the invention relates to a composition comprising a hydrofluoroolefin and a stabilizer.
2. Description of Related Art
Fluoroolefins and certain other compounds, such as CF3I, have been proposed as replacements of chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons which, conventionally, have been used as working fluids, refrigerants, solvents, blowing agents, and the like. Fluoroolefins and CF3I are characterized as having a low global warming potential (GWP) and little or no ozone depletion effect and, thus, are more environmentally friendly compared to chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. Moreover, fluoroolefins and CF3I have excellent refrigeration performance and generally are nontoxic and nonflammable.
The refrigerant's low global warming is due, in part, to the fact that these compounds are less chemically and thermally stable than their predecessor refrigerants. More particularly, fluids that have low GWP values typically have a reactive site, such an alkene's double bond, that advantageously increases the rate of decomposition in the atmosphere thus producing a short atmospheric lifetime. This reactive site in the molecule is usually not reactive enough to cause the substance to be so unstable that it's utility as a refrigerant or solvent in degraded. While these properties are typically maintained at low temperatures, the stability of low GWP refrigerants and solvents is jeopardized when they contact with conventional materials of construction of refrigeration systems at high temperatures (e.g., ≧50° C.).
It is also possible that the reactive sites of the low GWP materials can be the source of reaction during use and also during storage. Reactions such as polymerization or decomposition have been seen when some of these low GWP substances have been stored under extreme conditions. Even though many of these low GWP materials are fairly stable during use, they are measurably less stable than the long lived hydrofluorocarbons they replace.
In substituting low GWP substances which have this necessary reactive site in the molecule, there is a need to stabilize the fluid during storage and use if the fluid is subjected to extreme temperatures or long storage times. While conventional stabilizers for low GWP working fluids are often soluble in conventional lubricating oil, they are not soluble in the refrigerant itself. A stabilizer that is soluble in the refrigerant, and more preferably soluble in both the refrigerant and lubricant, would be advantageous.